I am trying to find out for you where you would place these on your sd card

EDIT: Covers Path - SD:/images/
This is where box art is downloaded to and displayed from. All images must be sized in multiples of 4 or they won't show up.
Official sizes:
2D covers = 160x224
3D covers = 176x248

WBFS manager also downloads the 2D cover files to a folder on your hard drive, typically in My Documents, you can also copy those to your SD, provided they conform to the sizing convention they should show up.